This invention relates to a hydraulic seal arrangement.
More particularly, the present invention relates to a hydraulic seal arrangement between two shafts, especially of a gas turbine engine, which rotate relative to each other.
A hydraulic seal arrangement of the type specified is known from Specification DE 199 16 803 A1. A similar seal design is also presented in Specification EP 1103706 A2.
Such hydraulic seal arrangements are provided between two shafts which rotate at different speeds relative to each other, for example a low-pressure shaft and a high-pressure shaft, to insulate an area with relatively high pressure from an area with relatively low pressure. The basic principle of such hydraulic seal arrangements is comparable to a centrifugal-effect siphon.
These hydraulic seal arrangements are also used to supply lubricant or hydraulic fluid to at least one bearing which locates the two shafts relative to each other.
The seal arrangement described in Specification DE 199 16 803 A1 works satisfactorily, but is disadvantageous in that it entails a higher installation effort, depending on the design conditions. Furthermore, an annular groove must be provided on the second, outer shaft (high-pressure shaft), this incurring additional manufacturing effort. Therefore, this design cannot be used, or can be used only to a limited extent, on gas turbine engines on which a turbine disk forms one part with a bearing shaft, for example. Furthermore, it can be disadvantageous that the seal is situated close to the turbine, as a result of which the inner portion of the hydraulic seal arrangement is to be connected to the low-pressure turbine shaft (first, inner shaft) by means of a relatively long shaft. This arrangement is likely to result in rotor-dynamic problems.